Jean-Pierre MartineauandClaude Opus 5.5
3e251a9707
The same rewrite as for the core package. The physical screen of a handheld is now the display, and the computer is the handheld. The comment on FONT_ENV now says that it is the environment variable. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
85 lines
3.1 KiB
Python
85 lines
3.1 KiB
Python
# SPDX-License-Identifier: Apache-2.0
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"""The bytes that a terminal sends for each keyboard key: what the emulator types into MeshTerm.
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Both front ends use this module. The handheld reads key codes from the event device file
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of the keyboard, and the window reads them from the desktop. Each front end changes its
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own events into a :class:`Key`, and :func:`encode` spells it as xterm does. The spelling
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of xterm is the contract, because prompt_toolkit parses it. A desktop terminal that runs
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``--platform cardputer-zero`` sends it too. Thus the TUI cannot tell the three apart:
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* Shift with F4–F8 is xterm's ``CSI 1;2 S`` / ``CSI 15;2 ~`` …, which prompt_toolkit
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reads as F16–F20. These are the Shift bank of the Cardputer deck
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(:data:`~meshterm.ui.tui.fkeys.CARDPUTER_ZERO_DECK`).
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* A modified arrow, Home, End, Page key, or F-key has the modifier parameter of xterm
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(``1 + Shift + 2·Alt + 4·Ctrl``). Thus Ctrl+PgUp is ``CSI 5;5 ~``, the section jump.
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* Ctrl with a letter is the C0 control of that letter. Alt with any keyboard key is ESC,
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then that keyboard key.
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"""
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from __future__ import annotations
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from dataclasses import dataclass
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#: The keyboard keys that are not text, by name. Arrows, Home, and End take the modified
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#: form ``CSI 1;m X`` of xterm. The others take ``CSI n;m ~``.
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_CURSOR_FINAL = {"up": "A", "down": "B", "right": "C", "left": "D", "home": "H", "end": "F"}
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_TILDE = {
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"insert": 2,
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"delete": 3,
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"pageup": 5,
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"pagedown": 6,
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"f5": 15,
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"f6": 17,
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"f7": 18,
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"f8": 19,
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"f9": 20,
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"f10": 21,
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"f11": 23,
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"f12": 24,
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}
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_SS3 = {"f1": "P", "f2": "Q", "f3": "R", "f4": "S"}
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_PLAIN = {"escape": "\x1b", "enter": "\r", "tab": "\t", "backspace": "\x7f"}
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@dataclass(frozen=True, slots=True)
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class Key:
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"""One key press: a named keyboard key (``"up"``, ``"f4"``, ``"enter"``) or its text."""
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name: str = ""
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text: str = ""
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shift: bool = False
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ctrl: bool = False
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alt: bool = False
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def encode(key: Key) -> str:
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"""The bytes that a terminal sends for ``key``, or ``""`` if no spelling exists for it."""
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modifier = 1 + key.shift + 2 * key.alt + 4 * key.ctrl
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name = key.name
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if name in _CURSOR_FINAL:
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final = _CURSOR_FINAL[name]
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return f"\x1b[{final}" if modifier == 1 else f"\x1b[1;{modifier}{final}"
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if name in _SS3:
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final = _SS3[name]
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return f"\x1bO{final}" if modifier == 1 else f"\x1b[1;{modifier}{final}"
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if name in _TILDE:
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number = _TILDE[name]
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return f"\x1b[{number}~" if modifier == 1 else f"\x1b[{number};{modifier}~"
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if name == "tab" and key.shift:
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return "\x1b[Z"
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if name in _PLAIN:
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sequence = _PLAIN[name]
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return "\x1b" + sequence if key.alt and name != "escape" else sequence
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text = key.text
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if not text:
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return ""
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if key.ctrl and len(text) == 1:
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lower = text.lower()
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if "a" <= lower <= "z":
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text = chr(ord(lower) - 96)
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elif text in "@[\\]^_":
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text = chr(ord(text) & 0x1F)
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elif text == " ":
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text = "\x00"
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return "\x1b" + text if key.alt else text
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